Steps:
1. Pack the lemons in enough salt to cover. Pack for a week.
2. Dice tuna and scrape the meat from the fatty parts outside of the loin. Dice the shallots, onions and chives, and chop the parsley.
3. Make mayonnaise with green peppercorns in brine, or mix the peppercorns into purchased existing mayonnaise.
4. Slice the salmon and cucumbers, and dice the tomatoes. Wedge the lemons and cut into small sections.
5. In a bowl mix the tuna, a pinch of onion, capers, chives, shallots, and parsley. Mix with olive oil and mayonnaise: just enough to bind. Season with lemon juice and salt and pepper to taste.
6. Put a square cut of smoked salmon in the center of a plate, and place a ball of tuna tartare on top. Arrange cucumbers and lemon wedges around the tartare, and sprinkle diced onion and tomato around plate to garnish.